Get Started with Cloud Storage on Android

Cloud Storage for Firebase lets you upload and share user generated content, such as images and video, which allows you to build rich media content into your apps. Your data is stored in a Google Cloud Storage bucket, an exabyte scale object storage solution with high availability and global redundancy. Cloud Storage lets you securely upload these files directly from mobile devices and web browsers, handling spotty networks with ease.

Prerequisites

If you haven't already, add Firebase to your Android project.

In your project-level build.gradle file, make sure to include Google's Maven repository in both your buildscript and allprojects sections.

Set up public access

Cloud Storage for Firebase provides a declarative rules language that allows you to define how your data should be structured, how it should be indexed, and when your data can be read from and written to. By default, read and write access to Storage is restricted so only authenticated users can read or write data. To get started without setting up Authentication, you can configure your rules for public access.

This does make Storage open to anyone, even people not using your app, so be sure to restrict your Storage again when you set up authentication.

Add Cloud Storage to your app

Add the dependency for the Cloud Storage Android library to your module (app-level) Gradle file (usually app/build.gradle):

implementation 'com.google.firebase:firebase-storage:17.0.0'

Set up Cloud Storage

The first step in accessing your storage bucket is to create an instance of FirebaseStorage:

FirebaseStorage storage = FirebaseStorage.getInstance();

storage = FirebaseStorage.getInstance()

You're ready to start using Cloud Storage!

First, let's learn how to create a Cloud Storage reference.

Advanced setup

There are a few use cases that require additional setup:

• Using storage buckets in multiple geographic regions
• Using storage buckets in different storage classes
• Using storage buckets with multiple authenticated users in the same app

The first use case is perfect if you have users across the world, and want to store their data near them. For instance, you can create buckets in the US, Europe, and Asia to store data for users in those regions to reduce latency.

The second use case is helpful if you have data with different access patterns. For instance: you can set up a multi-regional or regional bucket that stores pictures or other frequently accessed content, and a nearline or coldline bucket that stores user backups or other infrequently accessed content.

In either of these use cases, you'll want to use multiple storage buckets.

The third use case is useful if you're building an app, like Google Drive, which lets users have multiple logged in accounts (for instance, a personal account and a work account). You can use a custom Firebase App instance to authenticate each additional account.

Use multiple storage buckets

If you want to use a storage bucket other than the default provided above, or use multiple storage buckets in a single app, you can create an instance of FirebaseStorage that references your custom bucket:

// Get a non-default Storage bucket
FirebaseStorage storage = FirebaseStorage.getInstance("gs://my-custom-bucket");

// Get a non-default Storage bucket
val storage = FirebaseStorage.getInstance("gs://my-custom-bucket")

Working with imported buckets

When importing an existing Cloud Storage bucket into Firebase, you'll have to grant Firebase the ability to access these files using the gsutil tool, included in the Google Cloud SDK:

gsutil -m acl ch -r -u firebase-storage@system.gserviceaccount.com:O gs://<your-cloud-storage-bucket>

This does not affect newly created buckets, as those have the default access control set to allow Firebase. This is a temporary measure, and will be performed automatically in the future.

Use a custom Firebase App

If you're building a more complicated app using a custom FirebaseApp, you can create an instance of FirebaseStorage initialized with that app:

// Get the default bucket from a custom FirebaseApp
FirebaseStorage storage = FirebaseStorage.getInstance(customApp);

// Get a non-default bucket from a custom FirebaseApp
FirebaseStorage customStorage = FirebaseStorage.getInstance(customApp, "gs://my-custom-bucket");

// Get the default bucket from a custom FirebaseApp
val storage = FirebaseStorage.getInstance(customApp!!)

// Get a non-default bucket from a custom FirebaseApp
val customStorage = FirebaseStorage.getInstance(customApp, "gs://my-custom-bucket")